1. Technical Field
The present disclosure relates to an apparatus for performing a surgical procedure and, more particularly, to an electrosurgical apparatus including an end effector having a pair of jaw members for providing a mechanical advantage at the end effector.
2. Background of Related Art
Electrosurgical instruments, e.g., electrosurgical endoscopic forceps, are well known in the medical arts and typically include a housing, a handle assembly, a shaft and an end effector assembly attached to a distal end of the shaft. The end effector includes jaw members configured to manipulate tissue. Typically, the electrosurgical instrument is operatively and selectively coupled to an RF power source that is in operative communication with a control system for performing an electrosurgical procedure. Electrosurgical endoscopic forceps utilize both mechanical clamping action and electrical energy to effect hemostasis by heating tissue and blood vessels to coagulate, cauterize, seal, cut, desiccate, and/or fulgurate tissue.
Typically, the jaw members include a highly conductive seal plate and are pivotably coupled to one another via one or more mechanical interfaces that provide a point of pivot for one or both jaw members. For example, in certain instances, a cam slot including a cam pin operably disposed therein and a pivot pin are operably coupled to the end effector and/or one or both jaw members. In this instance, the cam slot, cam pin and pivot pin collectively pivot and close one or both jaw members. For added structural integrity, the cam slot, cam pin and pivot pin are fabricated from metal.
In certain instances, to facilitate moving the jaw members from an open position for grasping tissue to a closed position for clamping tissue (or vice versa) such that a consistent, uniform tissue effect (e.g., tissue seal) is achieved, one or more types of suitable devices are operably associated with the electrosurgical endoscopic forceps. For example, in some instances, one or more types of springs, e.g., a compression spring, are operably coupled to the handle assembly associated with the electrosurgical endoscopic forceps. In this instance, the spring is operatively associated with a drive assembly to facilitate actuation of a movable handle associated with the handle assembly to ensure that a specific closure force between the jaw members is maintained within one or more suitable working ranges.
In certain instances, the shaft bends or deforms during the course of an electrosurgical procedure. For example, under certain circumstances, a clinician intentionally bends or articulates the shaft to gain mechanical advantage at the surgical site. Or, under certain circumstances, the surgical environment causes unintentional or unwanted bending or flexing of the shaft, such as, for example, in the instance where the shaft is a component of a catheter-based electrosurgical endoscopic forceps. When the shaft is bent or deformed, there are frictional losses associated with a drive wire or cable translating through the shaft from the spring in the housing, which, in turn, diminishes, impedes and/or prevents effective transfer of the closure force that is needed at the jaw members. Moreover, the frictional losses also lessen the operative life of the spring, which, in turn, ultimately lessens the operative life of the surgical instrument. The spring allows for more flexibility when passing through curves in the catheter.
An increased mechanical advantage and/or mechanical efficiency with respect to transferring the closure force(s) from the handle assembly to the jaw members may prove advantageous in the relevant art.